Centrifs don’t have as high a compression ratio as positive displacement compressors but they compress a lot higher volume of refrigerant. They are the choice for large tonnage applications. We have a 9 mega watt system that we look after. A common issue with centrifs is surging: when there is low load, the compressor tries to suck, stalls then tries again. This causes the impeller and high speed shaft to rock forwards and backwards causing severe damage. There is a proximity sensor to shut the machine down in this condition but grinding of the impeller against the casting can still occur. After we re-built the compressor we installed controls to shut down the chiller when the process stopped. Should have been like that from commissioning but we were only brought in after the customer started having issues with the installer. Now we have got the machine to settle down- the customer are over the moon Read More